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Equipment right sizing versus customer demands, need your input.

Have a client with a large new home (3560) being built that I bid 6 months ago and listening to the customer requests I sized the systems at 84kbtu total like every other company and got the job. It is now time to do the install and I have since learned the value of right sizing equipment and not using the ol' 500sqft method anymore.

The issue is that I have now taken a closer look at this home and title 24 (prepared by an independent company) calls for a minimum of 36kbtu. I now want to revise the system down for efficiency and longevity issues to 72kbtu which will only change the condensers down a half ton each, no change on the furnace coil to stick with the same seer/eer ratings and maintain proper airflow. I have of course explained in great detail the benefits of doing this and the customer does not like the fact of having a rightsized system versus one that will cool down faster when the want. I have never had this be an issue for me because my customers go with my recommendations. They have a family member who has built homes in the past influencing their decisions to stick with the bigger system because in his opinion that is better. I have spent some time trying persuade both of them to leave the practices of the past and accept something new that is better for them.

Rather than getting in a pissing match with this family member which may cost me the job, the advice I am looking for is that if they do not go with my revised recommendations do you make your customers sign anything that they are aware that the systems are over-sized and may cause humidity, efficiency and longevity issues?

I would write a letter nicely explaining the major problem that could arise from oversizing A/C. I would only list one main concern of yours. I would not try to use the letter as a way to persuade them. That might tick them off.

Explain that you don't want there to be any misunderstandings and ask them to sign off on it. Good luck.

Explain to them by oversizing they won't see the SEER that they are paying for when it comes to thier power bills. Correct sizing is essential to obtian rated SEER in real world conditions. Explain it from a "how long does an AC run before it gets cold" angle.

did legislation change in time between bidding and current time? if it did not, i see no purpose for asking customer to sign anything if you yourself offered him that the same thing which you now declare as inefficient.

if legislation changed, that can be your argument to make changes, if not, you simply picked wrong time to demonstrate your new awareness.

Have a client with a large new home (3560) being built that I bid 6 months ago and listening to the customer requests I sized the systems at 84kbtu total like every other company and got the job. It is now time to do the install and I have since learned the value of right sizing equipment and not using the ol' 500sqft method anymore.

The issue is that I have now taken a closer look at this home and title 24 (prepared by an independent company) calls for a minimum of 36kbtu. I now want to revise the system down for efficiency and longevity issues to 72kbtu which will only change the condensers down a half ton each, no change on the furnace coil to stick with the same seer/eer ratings and maintain proper airflow. I have of course explained in great detail the benefits of doing this and the customer does not like the fact of having a rightsized system versus one that will cool down faster when the want. I have never had this be an issue for me because my customers go with my recommendations. They have a family member who has built homes in the past influencing their decisions to stick with the bigger system because in his opinion that is better. I have spent some time trying persuade both of them to leave the practices of the past and accept something new that is better for them.

Rather than getting in a pissing match with this family member which may cost me the job, the advice I am looking for is that if they do not go with my revised recommendations do you make your customers sign anything that they are aware that the systems are over-sized and may cause humidity, efficiency and longevity issues?

did legislation change in time between bidding and current time? if it did not, i see no purpose for asking customer to sign anything if you yourself offered him that the same thing which you now declare as inefficient.

if legislation changed, that can be your argument to make changes, if not, you simply picked wrong time to demonstrate your new awareness.

what calculation are you using now, manual j?

All of us submitted our bids before the homeowner provided the title 24 (manual J) Docs so we were all shooting in the dark.

No, not required in our area and all the homes that did have HRV’s installed are either removed or turned off. We have a new law that requires whole house fans in all new homes so that takes care of the fresh ventilation I guess.

Northern Cali, very low humidity. I have seen systems over-sized by more than a ton and not ever had humidity or smell issues.

My question is: do you provide fresh air ventilation? This has nothing to do with humidity control. It has to do with purging indoor pollutants and renewing oxygen. Maybe you have answered the question.
Regards TB

My question is: do you provide fresh air ventilation? This has nothing to do with humidity control. It has to do with purging indoor pollutants and renewing oxygen. Maybe you have answered the question.
Regards TB

Answered above but here it is again.

No, not required in our area and all the homes that did have HRV’s installed are either removed or turned off. We have a new law that requires whole house fans in all new homes so that takes care of the fresh ventilation I guess. Commercial requires 15% fresh air though